The purpose of the I-joist is to create a silent-floor system. It’s a higher-end floor system, but it almost completely eliminates squeaking or creaking in the floor.
This engineered wood is approved by an engineer, and usually has a very specific purpose (rather than for general carpentry).
A few more examples of engineered wood are:
- LVL (laminated veneered lumber) Beams
- Parallam Beams
- Glulam Beams
Engineered wood is far more stable in terms of growth and shrinkage. While dimensional lumber will expand and contract over time, engineered wood is very minimally affected by temperature changes.
The cost of engineered wood may be minimal compared to how beneficial it can be to a project. For example, if you had a basic framing package for $25,000, upgrading to an advanced I-joist system would cost roughly $1,500 more. In the grand scheme of building a house, this isn’t a whole lot of money to upgrade to a much more effective system.